Relay, microphone, or other sensitive-contact device.



P. 0. PBDERSEN.

RELAY, MICROPHONE, OB OTHER SENSITIVE OONTAOT DBVIOB.

APPLICATION FILED MAY 28, 1912.

Patented Deo. 29,1914

FEDER OLUF PEDERSEN, OIE' COPENHAGEN, DENMARK. b

assenso.

Specication of Letters Patent.

Patented Dec. 29, iigill.

Application filed May 28, 1912. :'lSerial No. 700,289.

.tiven'ess in relays, microphones or other sensitive contacts can be obtained b -small mutual displacements of the electro es, it being,

. however, provided that thesaid displace- Bti ments take place in quite distinct manners. @ne of the methods used is the following: 'After the parts forming'the sensitive contact in mechanical respect have assumed some position of equilibrium, one or more of the electrodes or other parts forming the sensitive contact or parts of same are drawn a little away from ythe remainder of the parts of-which the sensitive contact consists. As an example of a construction according to this principle the following may be named: in an ordinary carbon grain microphone the parts are arranged in such a manner that the diaphragm can assume' two' or eventually more distinct -positions 'relatively to, the grain box; One' of these positions is the resting position of the 'microphone' In the same the pressure between the single-parts of contact is comparatively'considerable, and the mioroplfone'is rather Yunsensitive; When the microphone isV to be used the 'diaphragm' is brought' into they other position (or into one of the other positions). Ilhis latter position is called the working position of the microphone. ln this position' -the diaphragm is removed a small ,distance from the grain box, compared to thev resting position, and the grains in all essentials 'retaining the same positions and situations as in the restingposition, the pressure between the diaphragm andthe grains becomes smaller -in the working position than in the resting position, and this'faot eiiec s a' great V"augmentation of the sensitiveness of the microphone. From this it appears that even if the microphone does only obtain the great sensitiveness inthe working position, the resting position is for -th'e very attainment of the augmented sensitiveness at least just as important, the result being only 'obtainable through the quite distinct coperation betwen the two positions. The microphone retains its augmented sensitiveness as long as the .grams preserve their position from the resting position. lf this position be disturbed through shakings or in any other manner the microphone reassumes its nor-V mal sensitiveness. As lthis break down can only happen under influence of loud speaklng it will often be appropriateto arrange the construction in a somewhat dierent manner as indicated below.

ln the above it has been essentially presumed that the microphone when not used was found in the condition of rest, andthe working position arose from the fact that the diaphragm was a little removed from the carbon box. However, it may also bearranged in such a manner that the microphone is normally in its working position and is only temporarily brought into its restmg position. As regards attainment of the sensitiveness the eii'ect will essentially be the same. By way of example the following. way of executing the two modifications may be named: In the former case the diaphragm can normally when themicrophone isv not used be pressed against the grain box by a spring; vthe working position is then produced bytaking od' the spring pressure. ln latter case the resting position is produced by the diaphragm being pressed against the grain box, while the diaphragm when the pressure is taken o spontaneously returns to the working position. Through the em- Vwhich the acting parts are relatively near to each other, and a working position in which the parts are a little remote from 'each other compared to the resting position so that the augmented sensitiveness is vproduced by the microphone being brought from the restingto the working-position. The manner'itselin in which the positions and the transition Aes ' shape is somewhat modified. It is likewise of secondary importance whether the. establishing of a restingand the workingpositions and the transition from one to the other is effected by ressing directly buttons, keys, adjustingevers, or the hke, or

whether the necessary adjustments are efl fected automatically by the telephone or the microphone being taken oi the hook, by turning of themicrophone, by closing or interrupting of certain electrlc clrcults, or in other similar manners. Instead of one single working position it might be appropriate to have more, .for instance of varying sensitiveness.

For sake of clearness displacement of the disphragm has only been mentioned in the above; however, there is no objection to the displacementalso being effected with other of the electrodes of the nicrophone or with other of the parts forming the sensitive contact. Likewise for sake of clearness only microphones are referred to; but

the invention just-as well relates to relays with lmicrophonic contactsas well as to other sensitive contacts.

By way of example two constructions of y microphones accordlng to the invention are descri ed and illustrated, Figure 1 showing one form'in section and Figs. 2 and 3 another form respectively in section and front elevation. Y

l designates the mouth piece of the microhone, 2 the diaphragm, 3 the ain chamr, 4 the rear carbon electro e, 5 a felt grain retaining ring, 6 a push button arranged on a flexible spring 7, which again carries a 'small projection 8. As long as the button 6 is -in the osition shown in Fig. 1, the entire microp one is in its normal position which here corresponds to the working position. .In case the button remains unaltered in the shown position, the/ microphone acts quite as usual and with the normal sensitiveness. If the button 6 is pressed sin,l so that the shoulder 11 rests against the capsulel12, the projection 8 is at the samev time ressed against the diaphragm 2 and thls'again against the grains in the chamber 3. In this position the microphone is rather unsensitive; but if the button 6 is again released, so that the parts 6, 7 and 8 re-assume the positions shown in Fig. 1, the diaphragm will return too and the pressure between the same and the grains and between the latter mutually will be much diminished and the sensitiveness much augmented. The pressure on the 'button 6 can be exercised by the finger, as wanted by the person speaking, or automatically as indicated in Fig. 1 in which 9 and 10 indicate two positions of a rod.

When the telephone is not used and is thus hanging on the fork or hook, the rod occupies the position 9; as soon as the telephone is taken oil' the fork, it assumes the'position 10. During the passage from the position 9 .to .10 the button 6 is temporarily pressed in. When the telephone is replaced ,on the fork, the rodvre-assu'mes the position 9.

Another modification is shown in Figs. 2 and 3. Here 13 indicates an iron ring fixed on the diaphragm, and 14 the pole shoes of an electro-magnet consisting of the iron frame 15 and the coils 16. The windings of the electromagnet are connected to the terminals 18 and 19, with whichV also the wires of the microphone are connected. When the microphone is without current, the pole shoes 14 only exercise a slight attraction on the ring 13, andthe microphone is in its resting position. As soon as the microphone is energized by current, the pole shoes 14 attract the rin ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim "and dAesire to secure by Letters Patent of U.. S.

13 and the da hragm enters into the wor 1. A device of the character described,

employing a finely divided .variable resistance material as an essential element of the transmitting medium, and means for placing the particles of said material under additional pressure while the device is not being used and then relieving said additional pressure when the device isV being used, in order to augment the sensitiveness of said material.

2. In a device of the character described, the combination of a pair' of electrodes, and means for placing said electrodes under additional pressurewhile the device is not rin use and then relieving the pressure while the device is being used to th "ebyincrease the sensitiveness of said elecv rodes.

3. The method of augmenting the sensitiveness of a microphone or like instrument, employing a linely divided variable resistance material as an essential part of the transmitting medium, which consists in compressing said materi 1 while the instrument is not being use for transmission permit the particles of the material to loosen and resume a condition in which they may be employed for transmitting purposes.

In Witness whereof, I have subscribed my signature, in the presence of two witnesses.

PEDER OLUF PEDERSEN.

Witnesses:

F. G. ERICHSEN, HENRI PoULsEN. 

